Structural and vibro-acoustics optimization of a car body rear part (Master thesis)
Modeling a vibro-acoustic problem and use of reduced order models in the automotive field (Cnam/LMSSC)

At LMSSC, Paris, June 14th 2023, 2 p.m.

Tommaso Landi
Doctorate, Dipartimento di Ingegneria Industriale (DIIn), Università degli Studi di Salerno (UNISA), Fisciano, Italy

The first part is devoted to the master thesis work carried out at Stellantis Spa (Naples). The objective of the thesis (from January to July 2022) was to increase the vibro-acoustic comfort inside the passenger compartment. The Sound Pressure Level (SPL) was simulated at the driver's ear considering a compressible fluid inside an elastic car chassis. Various studies related to the torsional stiffness of the car such as sensitivity analyses of material parameters and topological optimisations have been investigated. The new performance has shown a decrease of the SPL at the driver's right ear and the results have been published in [1].

The second part deals with the work done at the CNAM/LMSSC. The objective is to develop and use projection based reduced order models (ROM) for automotive applications. In the automotive industry, the number of degrees of freedom can become prohibitive using the finite element method, in particular for frequency response functions (FRF). Firstly, a displacement-pressure vibro-acoustic formulation [2] has been implemented in an in-house finite element code. Comparisons have been carried out between Patran/Nastran and the in-house code for validation. Very good agreements in terms of coupled eigenfrequencies and eigenmodes have been obtained for simple geometries and meshes. Secondly, the use of ROM using uncoupled bases has been performed. Very good accuracy and speed-up factors are shown to calculate the SPL, by exciting the external structure. Finally, those implemented techniques have been tested on a car like geometry.

Références :

  1. R. Citarella, T. Landi, L. Caivano, G. D'Errico, F. Raffa, M. Romano, E. Armentani, Structural and vibro-acoustics optimization of a car body rear part, Applied Sciences, 13 (6), 3552 (25 pages), 2023. doi
  2. H. J.-P. Morand, R. Ohayon, Fluid structure interaction, John Wiley & Sons, 220 pages, ISBN : 978-047-194-459-1, 1995.